A B737-300 captain reported losing battery power in cruise flight. An emergency was declared and a d...

Narrative:

We were level at FL330 on leg 2 of first day of a three-day trip. Both dc fail lights illuminated; and autopilot and heading failed. We referenced the QRH; battery charger circuit breaker (behind first officer) and switched the battery bus circuit breaker (behind the captain). Both checked okay and all other circuit breakers checked okay. We checked TR1; 2 and 3. All okay. We checked a/C power; it was okay. We checked the battery; it showed zero (0) volts and amps. ZZZ was directly in front of the aircraft about 80 NM and in sight. We decided to divert there and not continue. I briefed the flight attendants. I informed the passengers we had a problem and were going to stop to have it checked. The center was helpful; however; I declared an emergency to receive priority handling. All checklists were accomplished. The visual approach; landing and taxi to gate were uneventful. We called dispatch; maintenance control; and the chief pilot on call. All were debriefed and all questions were answered. We got a new aircraft; and continued to our destination. There were possible altitude errors due to the aircraft malfunctions and high workload of both pilots.

Original NASA ASRS Text

Title: A B737-300 Captain reported losing battery power in cruise flight. An emergency was declared and a divert to nearest suitable airport was accomplished.

Narrative: We were level at FL330 on leg 2 of first day of a three-day trip. Both DC Fail lights illuminated; and autopilot and heading failed. We referenced the QRH; battery charger circuit breaker (behind First Officer) and switched the battery bus circuit breaker (behind the Captain). Both checked okay and all other circuit breakers checked okay. We checked TR1; 2 and 3. All okay. We checked A/C power; it was okay. We checked the battery; It showed zero (0) Volts and Amps. ZZZ was directly in front of the aircraft about 80 NM and in sight. We decided to divert there and not continue. I briefed the Flight Attendants. I informed the passengers we had a problem and were going to stop to have it checked. The Center was helpful; however; I declared an emergency to receive priority handling. All checklists were accomplished. The visual approach; landing and taxi to gate were uneventful. We called Dispatch; Maintenance Control; and the Chief Pilot on Call. All were debriefed and all questions were answered. We got a new aircraft; and continued to our destination. There were possible altitude errors due to the aircraft malfunctions and high workload of both Pilots.

Data retrieved from NASA's ASRS site as of April 2012 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.

Attributes
ACN	887623
Time
Date	201005
Local Time Of Day	0601-1200
Place
Locale Reference	ZZZ.Airport
State Reference	US
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	B737-300
Operating Under FAR Part	Part 121
Flight Phase	Cruise
Component
Aircraft Component	DC Battery
Person 1
Function	Captain
Qualification	Flight Crew Air Transport Pilot (ATP)
Experience	Flight Crew Last 90 Days 152
Events
Anomaly	Aircraft Equipment Problem Critical Deviation - Altitude Excursion From Assigned Altitude Deviation - Procedural Clearance

A B737-300 captain reported losing battery power in cruise flight. An emergency was declared and a divert to nearest suitable airport was accomplished.